Musannaf Ibn Abi Shayba 22:163

Al-Fadl ibn Dukayn narrated to us, he said: Musa ibn Ali narrated to us, he said: I heard my father narrating from Uqbah ibn Amir, he said: The Messenger of Allah (may Allah bless him and grant him peace) came out to us while we were in the Suffah. He said: "Which of you would like to go out every day to Buthan or al-Aqiq and bring from there two large-humped she-camels without committing a sin or severing ties of kinship?" We said: "Yes, O Messenger of Allah, we all would like that." He said: "Does one of you not go out to the mosque and learn or recite two verses from the Book of Allah? That is better for him than two she-camels, and three is better for him than three, and four is better for him than four, and [so on] according to their number in camels."